Not hot- nor cold-blooded, dinosaurs were `in between`

New York: Were dinosaurs hot-blooded like birds and mammals or cold blooded like reptiles? Well, they were somewhere "in between".

Scientists evaluated the metabolism of numerous dinosaurs using a formula based on their body mass.

"We found that dinosaurs had growth and metabolic rates that were actually not characteristic of warm-blooded or even cold-blooded organisms," said evolutionary biologist Brian Enquist from University of Arizona.
"Instead, they had growth rates and metabolisms intermediate to warm-blooded and cold-blooded organisms of today," he added.

The researchers called creatures with this medium-powered metabolism "mesotherms".

The study assessed 21 species of dinosaurs as well as a range of mammals, birds, bony fish, sharks, lizards, snakes and crocodiles.
"In short, they had physiologies that are not common in today`s world," said Enquist.

Modern animals such as this leatherback turtle have a similar "in between" metabolism.